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American [ Castanea dentata (Marsh) Borkh.] × Chinese [ Castanea mollissima Blume] chestnut (Fagac, ae) hybrids are a novel system in which to study influences of phytopathogenic fungi and woody plant hybridization on herbivore susceptibility, as the hybrids are well characterized with regard to resistance to the chestnut blight fungus [ Cryphonectria parasita (Murr) Barr ( Endothia) Diaporthales: Valsaceae] and variability is present. We chose two groups of resistance-rated backcross chestnut that shared an F1 parent and had different American parents. Foliage from both backcross groups and the parent trees was sampled on three dates for use in feeding assays with gypsy moth larvae [ Lymantria dispar (L.) [Lepidoptera: Lymantriidae], adult Japanese beetles [ Popillia japonica Newman (Coleoptera: Scarabaeidae)], and fall webworm larvae [ Hyphantria cunea Drury (Lepidoptera: Arctiidae)], respectively. Foliar analyses were performed concurrently and included carbohydrate, tannin, and nitrogen content, toughness, and density. Blight resistance had almost no effect on herbivore performance or foliar chemistry. When the parent trees and backcross groups were compared, however, significant differences in gypsy moth performance and Japanese beetle consumption were evident. There were no differences in fall webworm consumption. Most foliar characteristics measured differed among chestnut genotypes at some point in the season, and all varied seasonally. No clear pattern emerges with respect to the relationship among blight resistance, herbivore susceptibility, foliar properties, and plant genotype, and more research is needed to separate these effects. [ABSTRACT FROM AUTHOR]

Plantation pine production in the Great Lakes region of the United States is often affected by a pine root weevil complex consisting of Hylobius pales (Herbst) and Pachylobius picivorus (Germar), which breed in dead and dying host material, and H. radicis Buchanan and H. assimilis (Miller, Benjamin & Warner), which attack and breed in healthyhost tissue. Baited pitfall traps were used to assess temporal and spatial changes in weevil populations in newly planted clear-cut stands over a 2-yr period, The number of weevils breeding in dying tissue comprised the majority of total weevils trapped, but their percentageof the total declined drastically by the 2nd yr because the slash used for brood development was used or became too degraded. The number of weevils attacking healthy host tissue became more prevalent by year 2, as the volatiles emanating from the newly established seedlings became more predominant. There was a positive relationship, between the number of weevils trapped in year 1 and the number of weevils trapped in year 2. A slow-release bait dispensing system was analyzed using specific synthetic compounds as baits. The synthetic alpha-pinene-ethanol mixture in slow-release polyethylene vials proved effective for monitoring the pine root weevil complex in recently planted clearcuts. The regional variability of weevil response to baited pitfall traps and the feasibility of using these traps to monitor pine root weevils in clearcut plantations are discussed. [ABSTRACT FROM AUTHOR]